Division of Health Sciences

Scientist receives $1.6 million to study ways to stop dangerous germ

Dr. Everett C. Pesci

GREENVILLE, N.C.
(Dec. 20, 2007)
—
Researchers at the Brody School of Medicine at East Carolina University are looking at ways to control a germ that causes serious infections in hospital patients and people who have cystic fibrosis with help from a five-year, $1.6 million grant from the National Institutes of Health.

Dr. Everett Pesci, an associate professor of microbiology and immunology, received the grant to study Pseudomonas aeruginosa, a bacterium that causes approximately 10 percent of hospital infections and chronic lung infections in approximately 90 percent of people with cystic fibrosis. Such infections are a major problem for hospitals and are the primary source of progressive lung dysfunction for C.F. patients.

Pseudomonas is resistant to many antibiotics, making treatment difficult. "We really need new compounds and new drugs that could have an effect on Pseudomonas," said Pesci, who has studied the bacteria for more than a decade.

Pseudomonas aeruginosa is an opportunistic pathogen, meaning it infects people with weakened immune systems. It is present in water, soil, on plants and many other surfaces. Approximately 10 percent of the population carries the bug, but it does not affect healthy people. "Most of us eat it, drink it and see it every day, and it doesn't bother us," Pesci said.

For people with HIV, C.F., burns, cancer and other conditions that weaken immune systems, however, Pseudomonas poses a serious threat, Pesci said.

To defuse that threat, Pesci is studying the chemical communication signals of Pseudomonas. Like many bacteria, Pseudomonas cells communicate with each other through chemical signals to keep track of the size of their population and the status of their environment. One chemical they use, which Pesci discovered, is the Pseudomonas Quinolone Signal. This signal controls the virulence, or ability to cause infection, of the bacteria. Without it, Pseudomonas is much less dangerous.

"They've sensed their population has grown to a level to allow them to do what they want to do," Pesci said, describing how the organism uses PQS. His study aims to learn more about how Pseudomonas makes PQS with the goal of helping control the bacteria.

"If we can inhibit production of the signal, we can make the organism less virulent," he said.

Dr. James Coleman, an ECU associate professor of microbiology and immunology, is collaborating with Pesci on the research and is a co-investigator on the NIH grant.